We propose the development of a new technique for measurement of ultrasonic transducer vibrational displacement and for measurement of ultrasonic field intensity in terms of vibrational displacement of particles within the acoustical field. The concept involves the facts that an ultrasonic signal reflected or scattered over a vibrating particle is phase modulated in proportion to the displacement and, where the phase modulation is small, the magnitude of the phase moduation is completely characterized by the ratio of the first side band amplitude to the carrier amplitude of the reflected sound beam. The proposed method involves narrow band measurement of the spectrum of a continuous wave sound beam reflecteed from the face of a transducer under test or scattered from within a biological medium through which a sound beam is propagated. The approach will be used for studies of loaded ultrasonic transducer vibrational characteristics, for mapping of the acoustical intensities of ultrasonic fields and for studies of the acoustical characteristics of normal and pathological tissue. The method ultimately may be applicable for noninvasive visualization of soft tissue structures in terms of regional acoustical intensity and acoustical attenuation.